read data from a TString

From: Gilles Quemener (quemener@isn.in2p3.fr)
Date: Tue Nov 16 1999 - 13:51:53 MET 




Dear Root Gurus,

I would like to know how one can read some floats and/or integers from

a TString already read from an ASCII file. I mean the equivalent of
the 

FORTRAN:

       integer count

       real x, y

       read(10,'(a)') line

* for instance do a test on the first character to see the line is
a comment

* line or to see if it contents useful variables and in that case:

       read(line,*) x, y, n

Here is what I would like to perform in Root/C++ for instance:



#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <iostream.h>
#include <fstream.h>
 
#include "TString.h"
 
int main()
{
  // ouverture fichier d entree:
   ifstream fin;           
   fin.open("essai.dat");
   if (!fin) {
     cout << "Unable to open essai.dat for reading\n";
     return(1);
   }

  // ouverture fichier de sortie:
   ofstream fout;           
   fout.open("essai.out");

  // create base string
   String line;
   Int_t count;
   Float_t x, y;

   ligne.ReadLine(fin);
   cout << line << endl;

  // tests if it is a comment line starting for instance by #,

  // otherwise reads a given number of variables in the line

  // depending of the line in the input file, the number and

  // the nature of the variables may vary, but is always

  // known before compilation  by the user (fortran

  //  programmer reflex!):

   if (line[0] == '#') {

      cout << line << endl;

      fout << line << endl; 

   }    

   else {

   // I would like somnething like that:

            line.sin(x,
y, count);                            
// reads from the line

   // or like:

            
sin << x << y << count << endl;       
// reads from the line

   }



 

   fin.close();

   fout.close();



   return 0;

}

Maybe this functionality already exists in the TString class, but I
do not know

how to use it.

Thank you for any help,

 

                        Gilles Quemener



-- 
_____________________________________________________________________
Gilles Quéméner                        tél: (33) (0)4-76-28-40-60
Institut des Sciences Nucléaires       fax: (33) (0)4-76-28-40-04
53, Avenue des Martyrs                 http://www.cebaf.gov/~quemener
38026 GRENOBLE cedex FRANCE

 












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